1. Division of Signal Processing and Biomedical Engineering, Department of Signals and Systems, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.
2. Center of Orthopaedic Osseointegration and Center of Advanced Reconstruction of Extremities, Department of Orthopaedics, Sahlgrenska University Hospital, University of Gothenburg, SE-431 80 Mölndal, Sweden.